1. Field of the Invention
This invention relates to an elongated lighting system and more particularly to an elongated and flexible lighting system using light emitting diodes as its light source.
2. Description of the Related Art
Perimeter or border lights (“perimeter lighting”) are commonly used on buildings to accentuate the structure, to draw customer attention to the building, and to provide safety lighting. Lighted signs are also commonly used with business to advertise products or to indicate whether the business is open or closed. Most conventional perimeter lighting systems and lighted signs use neon or fluorescent bulbs as the light source. Some of the disadvantages of these bulbs are that they have a relatively short life, are fragile and can consume a relatively large amount of power. Also, neon bulbs can experience difficulty with cold starting, which can lead to the bulb's failure.
Developments in light emitting diodes (“LEDs”) have resulted in devices that are brighter, more efficient and more reliable. LEDs are now being used in many different applications that were previously the realm of incandescent bulbs; some of these include displays, automobile taillights and traffic signals. As the efficiency of LEDs improve it is expected that they will be used in most lighting applications.
LEDs have been used in strip lighting applications. U.S. Pat. No. 4,439,818 to Scheib discloses a lighting strip that utilizes LEDs as the light source. The strip is flexible in three dimensions and is useful in forming characters and is capable of providing uniform illumination regardless of the characters selected for display. The strip comprises a flexible multi-layered pressure sensitive adhesive tape, having a plurality of triangle cutout sections on each side of the tape, with LEDs connected in a series with a resister. One disadvantage of this strip is that it cannot be cut to different lengths for different applications. Instead, different lengths of the strip must be used. Further, the light from the LEDs is not diffused to give the appearance of neon light, instead showing lighting “hot spots” along its length. This arrangement is not durable enough to withstand the conditions for outdoor use. The flexible tape and its adhesive can easily deteriorate when continually exposed to the elements.
U.S. Pat. No. 5,559,681 to Duarte, discloses a flexible, self adhesive, light emissive material that can be cut into at least two pieces. The light emissive material includes a plurality of light electrically coupled light emissive devices such as light emitting diodes. The material also includes electric conductors for conducting electric power from a source of electric power to each of the light emissive devices. While this lighting arrangement is cuttable to different lengths, the light it emits is not dispersed so that it resembles neon light. This arrangement is also not durable enough to withstand the conditions for outdoor use.
Flexible strip lighting using light bulbs has also been developed. U.S. Pat. No. 4,521,839 to Cook et al. discloses a strip lighting system comprising a string of electrically connected light bulbs contained within a flexible tube. The tube is of a waterproof material and is sealed at each end by a removable plug, so that the string of bulbs can be removed when necessary to be repaired or replaced.
One of the disadvantages of this strip lighting is that it is not suitable for replacing neon type perimeter lighting because the light from the individual light bulbs is not diffused and dispersed to give the appearance of a neon light source. Furthermore, no mechanism is disclosed for mounting the strip lighting to a structure. Another disadvantage is that the strip lighting uses light bulbs instead of LEDs, and light bulbs generally have a shorter life span and can consume more power than LEDs.
PCT International Application Number PCT/AU98/00602 discloses a perimeter light that uses LEDs as its light source and includes a light tube structure in which multiple LEDs are arranged within an elongated tube that diffuses or disperses the light from the LEDs. The perimeter light is used to highlight or decorate one or more features of a structure, such as a roof edge, window, door or corner between a wall or roof section.
One of the disadvantages of this light is that it is not flexible and that it cannot be cut to match the length of a building's structural features. Instead, the perimeter lighting must be custom ordered or is mounted without fully covering the structural feature. Also, the connectors between adjacent sections of lighting are bulky and result in a visible junction between the sections. The light's tube also significantly attenuates the light emitted by its LEDs, significantly reducing the light's brightness. There is also no apparatus or method for providing perimeter lighting that can be bent to match a curved structural feature of a building.